It’s been a wonderful summer in Berlin, filled with warm days and enough rain to keep everyone happy. Although we haven’t posted in a long time, our foraging excursions are still thriving on our botanical curiosity and are prodding us into the lush green spaces in and around the city. Today we will focus on a classic foraging activity that has deep cultural roots in Germany and Northern Europe, namely picking wild blueberries.

In Germany, picking mushrooms, nuts and berries is an exciting pastime for many nature lovers. Indeed, local laws guarantee the right to gather small amounts of nuts, mushrooms and berries in the forests surrounding Berlin. Still, picking European blueberries (Vaccinium myrtillum), or Heidelbeeren as they are known in German, is viewed with suspicion due to widespread but irrational fears of echinococcal disease. Known as the “Fuchsbandwurm” in German, this nasty tapeworm lives in foxes, mice, dogs and unlucky humans. A faulty belief that tapeworm eggs from wandering foxes stick to the surface of low-hanging berries and infect hapless foragers persists even among educated German foragers. Dear readers, this means only one thing: more blueberries for us and all informed, intrepid foragers around Berlin! Blueberry season is now coming to an end but at its height in late July the only limiting factor for the novice forager is the slow picking process. To solve this problem, clever Northern Europeans invented what is known in German as the Heidelbeerkamm or the blueberry comb which, true to its name, greatly reduces the effort of actually picking the berries by hand. Still, if improperly used the comb can damage the shrubs and might make it easy to go overboard in terms of quantities of berries picked. Wild blueberries around Berlin do look similar to American species, but there are crucial differences to keep in mind when foraging in the woods. For example, if you are used to picking northern highbush blueberries (Vaccinium corymbosum) in the eastern United States you may completely miss the blueberries growing all over the forests around Berlin: they are much shorter and lower to the ground than their American counterparts!

By now everyone knows that blueberries belong to the exclusive, but abused category of “superfoods”. European blueberries have the same health benefits as their cultivated relatives with the additional benefit of tasting a lot better. They are chock-full of antioxidants and, in particular, contain higher concentrations of anthocyanin than other type of berries. For a thorough review of the medicinal properties of the European blueberry please see here.

European blueberries prefer highly acidic soil and the sandy soil of the coniferous forests of Barnim (north of Berlin) provides an ideal habitat for their growth. Our favorite spots are in the forests next to Birkenwerder and Bernau (on the S1 line). The blueberry shrubs often create dense patches that cover large parts of the forests. They are quite common in the area, so if you hurry up there may still be some berries hanging!

Not long ago, the memory of chestnut trees was deeply rooted in the consciousness of rural communities around the Mediterranean. Known as sweet chestnut (Castanea sativa), the tree likely spread by hand from the Balkans and Asia Minor to other parts of Europe. It thrived in mountainous areas, where chestnuts were readily accepted as means to self-sufficiency by otherwise isolated communities. The American chestnut (Castanea dentata) served a similar function in the Appalachians, before it fell prey to an Asian fungus that put an end to the tree’s dominance in the forests of the Southeastern United States. In Corsica, the chestnut is firmly established in the island’s culinary traditions which impressively features chestnut beer. Likewise in Sardinia, as well as other parts of Italy, chestnuts have become an integral part of the country’s rich culinary tapestry.

Berlin is home to thousands of horse chestnuts (Aesculus hippocastanum) which casual observers may confuse with the lonely occurrences of sweet chestnut trees in parks and streets. Although the horse chestnuts do resemble the delicacy found in outdoor Christmas markets – roasted marroni – they are, in fact, mildly poisonous to both humans and horses. Take a look at the leaves and you will see that these trees have very different features. Once you’ve discovered the differences, you will never mistake horse chestnuts for the “real” chestnut again!

Despite its geographic adaptability and relative hardiness, the sweet chestnut is a paradoxically fragile creature. Once dormant, the tree can withstand temperatures of -20 degrees Celsius; on the other hand, a late spring or early fall frost can easily cause irreparable damage. Chestnuts prefer a moist, humid environment but well-drained soils. Prolonged periods of rain can stress the tree and, if drainage is not adequate, many specimens will drown. In Germany, as well as other parts of Northern Europe, sweet chestnuts were historically managed as coppice because their tall, straight suckers make perfect poles for growing hops. Unfortunately, Berlin lies slightly above the sweet chestnut’s northern limit of fruit production, which means that yields are low and erratic. Looking for and finding sweet chestnuts in Berlin is a reward all in itself, but is compounded by the rarity of such a find. Platforms like mundraub.org are quite helpful in indicating potential locations, as is our berlin plants map and your own happy wanderings around the city.

In a classic example of plant blindness, we kept missing a sweet chestnut tree on Schönfließer Straße next to Arnimplatz even though we frequently walk by there on our way to Con Calma – one of our favorite coffee shops in the area. This year the burrs looked promisingly full but once they fell to the ground, we were disappointed to see small and shriveled chestnuts inside. We did not fare better with an older duo of sweet chestnut trees in Volkspark Humboldhain despite their bountiful appearance. Refusing to give up our fat chestnut dreams, we pressed south toward Treptower Park where we spent a sunny afternoon wandering along the Spree River. Even there, despite a number of both young and old chestnut trees, the spiny burrs were full of disappointingly shriveled nuts. With some luck and tenacity we were able to find a single small but fat chestnut – the one featured in our photo. Perhaps some of our readers have had better luck?

The parsley family presents a formidable challenge for the urban forager. As a large family of typically aromatic plants, it contains many herbs such as cilantro, fennel, and lovage – all of which complement and enhance routine culinary experiences. Yet, nefarious members like hemlock (Conium spp.) or water hemlock (Cicuta spp.) contain powerful neurotoxins that can be deadly even in small doses. In Berlin, a cursory look around any green area is likely to yield a member of the parsely family – its distinguishing umbels being an easy tell-tale sign. However, for the inexperienced (and sometimes experienced) observer, the exact determination of the species can be difficult. In fact, proponents of cautious foraging philosophies often do away with the whole family, but instead of excessive caution we believe that better plant identification skills are warranted. In practice, this means relying on an established botanical key which unfortunately is a lot more work than simply performing a Google image search, or flipping through less detailed foraging books. (For Germany, we recommend the Schmeil-Fitschen botanical key Flora von Deutschland und angrenzender Länder.)

Keeping the above in mind, today we briefly focus on an interesting and lesser known member of the parsely family: bishop’s weed (Aegopodium podagraria).

This plant appears to have been a botanical rock star during the Middle Ages in Europe serving both as a pot herb and as a cure against gout – hence another popular name for it, goutweed. At that time, bishop’s weed had a permanent place in monastic gardens along with other multitalented plants, but today it is found pretty much everywhere in Europe and it is considered invasive in some parts of North America. The young leaves are typically harvested in the spring and can be eaten in salads or, when picked later in the season, cooked like your favorite greens. The blooms and the small fruits are also edible, with all mentioned parts packing a nutritious combination of vitamins, minerals and protein. The plant is particularly rich in potassium, calcium, zinc, and vitamins A and C.

Bishop’s weed is found all over Berlin but it prefers wet and shady places. It tends to spread through its extensive rhizomes, hence it is typically found in colonies of varied sizes. One of its common German names is Geißfuß or goat’s foot, which seems to accurately describe the unique shape of the leaves. Water hemlock (Cicuta virosa) looks quite different from bishop’s weed, and one way to help tell the difference is the absolute lack of bracts in bishop’s weed and their presence in water hemlock.

For the past couple of weeks, a slight fragrant aroma has been accompanying the movements of the wind throughout the streets of Berlin. Outdoor enthusiasts from the southeastern US would immediately recognize the scent of the native black locust (Robinia pseudoacacia) as an ephemeral summertime smell. Bees are also attracted to the pea-like clusters of blooms and black locust honey has a unique and much sought-after flavor which is even more appreciated due to the short blooming season of about two weeks.

In Germany, as elsewhere in Europe, introduced plants are differentiated by the rough date of the Columbian Exchange: those that appeared after 1500 AD are considered neophytes. Initially, the hard long lasting wood was used for making poles in the wine-growing regions of Germany. Black locust made its first recorded appearance in Berlin in the late 17th century as a rare ornamental, and it wasn’t until the late 18th century that the vigorous tree was advocated for cultivation in the Brandenburg area. Forgotten shortly thereafter, black locust only became noticeable again in Berlin after the Second World War when it began to colonize heavily bombed areas of the city.

The close shot of the specimen featured in our photograph was taken near Ostbahnhof, along the banks of the Spree river next to East Side Gallery. Although most of the strip is a large patch of mowed grass, the visitor will notice cherry trees (reminiscent of the Sakura campaign) and wild growing bushes of black locust and elderberries growing alongside the river. Just like elderberry, black locust blooms are edible and an easy way to prepare them is to dip them in your favorite batter and fry them. Childhood memories of the delicate taste of fried black locust flowers in a sweet batter are shared by many Southern Europeans. We also wanted to try them fried, but the recent heat wave in Berlin made us reconsider this method of preparation. Instead we made a simple infusion drink that was quite refreshing! Just steep the flowers in iced water, and then add your favorite syrup. This time we got carried away with a bit too much strawberry syrup (which can easily overpower the delicate fragrance of the black locust flowers) but it still tasted delicious.

Besides having delicious blossoms, black locust is an excellent building material and is often used as an alternative to the more exotic and less sustainable ipe wood. Black locust wood is so durable that it is a preferred material for posts and other outdoor structures. A great place to observe black locust trees in Berlin is Suedgelaende: a derelict train switchyard that has been taken over by urban nature and is now a protected reserve. This is a wonderful place to visit but there is definitely no plant-picking of any kind allowed!

The common reed (Phragmites australis) is a ubiquitous wetland grass of northern Germany whose tall golden stalks are currently quite noticeable in contrast to the surrounding green colors of spring. In urban landscapes around the world, reeds are used as a common form of biological treatment of wastewater which results in so-called constructed wetlands. Although this usage of Phragmites highlights a very modern utility of the plant aimed at dealing with increasing population densities in urban areas, common reeds possess a much older history intertwined with that of human settlement along the North and Baltic Seas.

Due to their natural abundance in northern Germany, Phragmites were traditionally used as a building material for thatched roofs. This kind of roof construction was widespread throughout Europe before the commercial availability of modern roofing materials. Yet, current demand for Phragmites in Germany still surpasses internal supply which means that a large portion of reeds used for thatched roofs has to be imported from Eastern Europe. In particular, the majority of imported reeds in Germany come from the Danube Delta in Romania, and questions have been raised regarding the sustainability of this practice in such a fragile ecosystem. Ironically, poor villagers in this isolated part of Romania cannot afford anything but Phragmites thatched roofs – in contrast to Germany where only the wealthiest are able to afford vacation homes with the status symbol thatched roofs.

Although Phragmites have a myriad other uses (for an interesting and informative ethnobotanical survey of the plant see here), what naturally interests the forager most is its edibility. The young shoots have a mild taste and can be eaten as vegetables, and the same goes for the roots that are tangled with the spring growth. These can be eaten raw or steamed, as preferred. Overnight, injured stems ooze out sweet syrup which can, according to our German plant book, be eaten as candy! Later in the fall, the seeds of the plant can be gathered and ground into flour or, for those who like to have fresh wild veggies in the winter, the seeds can be sprouted on your window sill.

The common reed is widespread in Berlin, and you are likely to find it along the shores of many lakes dotting the city. However, a lot of it grows in protected biotopes so care must be taken that only seeds are harvested from these places and the plants themselves remain unharmed. If you are interested in seeing a traditional German thatched roof, head to the Dahlem-Dorf U-bahnhof station, but don’t wait too long: Last week the roof caught on fire!

For the occasion of Germany’s reunification, the people of Japan donated a generous number of flowering cherry trees that line both sides of the Mauerweg right below the Bösebrücke bridge. The cherry trees are in full blossom at the moment, and their presence is duly appreciated by the locals as well as the growing number of tourists who wander this far north following the path of the former Berlin Wall. Yet the ostentatious beauty of the cherry trees overshadows the presence of a more recent botanical immigrant from the East: Japanese knotweed (Polygonum cuspidatum)*.

Much has already been written about the edible and medicinal virtues of this plant, which also happens to be an incredibly tenacious, invasive species with powerful root systems that can cause widespread structural damage. The young shoots are typically harvested in the spring when they are less than a foot tall and can be eaten either raw or cooked. Later in the year, the stems become hard and the tough outer shell needs to be pealed for consumption. Bees are fond of the plant’s small white blossoms which appear in the late fall, and it is said that they produce a mild but flavorful honey after pollinating these flowers. A quick Google search on Japanese knotweed recipes will give you many suggestions for how to eat the shoots, from simply sautéing them in butter to making rhubarb-like jams or pies. And, as Wild Man Steve Brill mentions in his description of this forager’s classic, the plant has myriad nutritional benefits.

However, enthusiastic foragers will quickly notice that the raw shoots taste quite sour and this is because the plant contains considerable amounts of oxalic acid, with the highest concentrations found in the leaves. Since oxalic acid can exacerbate medical conditions like kidney stones and rheumatism, only small amounts of Japanese knotweed should be ingested. (For more detailed information on the oxalate contents of different parts of the Polygonaceae family plants, take a look at the following abstract from the Food Chemistry journal.)

However, for foragers in heavily industrialized areas, oxalic acid indicates the possible presence of a much more threatening substance – namely lead. In the last few years, Japanese Knotweed has showed promising results in reducing lead levels in contaminated soils (the process is known as phytoextraction, which is a specific form of the phytoremediation already mentioned in our post on cattails). The high oxalic acid makes the lead more water soluble and hence the plant can absorb it more readily. In 2006, several Japanese “inventors” filed an application with the US Patent Office for a method of cleaning up lead-contaminated soil using Japanese knotweed.

Obviously, this should invite extreme vigilance on the part of the urban forager. After reading this rather disturbing news, we continued researching and found out that the area where we took these pictures has an average of 150-200 mg\kg of lead in the soil – about three times the naturally occurring level (although still considered relatively low in an industrialized setting according to US standards). We encourage all foragers in Berlin to use the public information made available by the Senate Department for Urban Development and Environment to check lead concentrations in their local foraging spots.

While this post may seem a bit discouraging to urban foragers, it is important to remember that our search for edible plants is hardly driven by hunger or immediate necessity; rather, it is a slow and deliberate movement towards a stronger relationship with the natural world despite the inevitable distance created by our urban habitation!

*There are two closely-related species of Polygonum in Berlin so it is also possible that the species in our photographs is Giant Knotweed (Polygonum sachalinensis). Everything we discuss about Japanese knotweed is likely valid for Giant knotweed.

Rivers, brooks and streams have served as fundamental cornerstones of most ancient civilizations, and many urban dwellers today are familiar with canals or waterways, whether natural or man-made. Plant life flourishes along rivers; the earliest “urban” foragers likely considered river banks as places of plenty. As mentioned earlier, the current natural features of the Northern European Lowlands were determined by the retrieval of glaciers, thus making the presence of water abundant. In terms of Berlin’s aquatic attractions, the Panke is at first sight unimpressive: a rerouted and mostly canalized rivulet less than thirty kilometers long, whose slow and meager current comes to a near standstill at some places along its route. It is hard to imagine that in the 19th century the Panke was home to many watermills, or that its waters were once used to brew beer.

We have come to know the Panke through many of our walks along its banks. As the river flows through Wedding and its namesake Pankow, it is only a short walk away from where we live and always provides us with a botanical adventure. Although we have encountered many interesting plant species along the Panke, today we briefly focus on one plant which most of you are familiar with and which is characteristic of wetlands.

Cattails are known the world over, and their characteristic brown flower spikes are hard to miss in the late summer and fall. Berlin has at least two species of wild growing cattails, Common Cattail (Typha latifolia) and Lesser Bullrush (Typha angustifolia). If you take a walk along the Panke, you are eventually bound to come across a colony of cattails and might think you have found an urban foraging treasure trove. The praises of cattails as an edible food have been sung for millennia by many cultures. It seems that nearly all parts of the plants are edible when harvested at the appropriate times. Certainly, the young shoots are edible in the spring, and if you like to get your hands dirty the starchy rhizomes are also edible at this time. Many other parts of the plant are delicious including the inner part of the stalk, the base of the leaves, and even the yellow pollen which apparently makes for a great pancake mix.

However, other uses for cattails are particularly interesting and useful, especially in view of the darker side of industrialism and its disastrous effects on the Panke. The industrial runoff severely polluted the Panke, which consequently became locally known as Stinky Panke. In the past couple of decades there have been major efforts to rehabilitate the river and the results are already promising. So what do cattails have to do with all this? Well, it just so happens that cattails have the ability to absorb contaminants and pollutants from water, in particular arsenic. This is a process known as phytoremediation, and cattails are a poster child for this type of organic water filtration system. While this is great news for the environment, it should definitely make you think twice before harversting cattails from the Panke!

What better occasion than the Vernal Equinox to unofficially kick-start our foraging season of 2012! As the temperatures begin to rise in the upcoming weeks, we will put away our coal bucket and wander around the city enjoying the spring sunshine and watching the slowly emerging young plants. Although Berlin has already started to regreen itself with plant life, the plentiful dead stalks of countless annuals and biannuals are a reminder of the relative foraging dearth of winter. However, there is one plant, a member of what the French call “legumes oubliés” (forgotten vegetables), which can provide plentiful nutrition for the knowledgeable forager throughout the late winter months.

Jerusalem artichokes (Helianthus tuberosus), or topinambur, is a common wild plant in Berlin. Many people find it hard to identify the withered stalk in March, but, during the summer, this tall growing plant is quite easy to identify as it is quite clearly related to the sunflower. The hairy stem and lack of seeds, however, are a distinguishing feature of the Jerusalem artichoke. Once you find a nice patch of plants in the summer, come back to it in the late winter and its delicious tubular goodies will be yours for the taking. Dig around as the tubers are spread out, but make sure to leave some for the next crop!

Also known as earth apples, Jerusalem artichokes have quite an interesting history. As American natives, they were quickly accepted as a root vegetable in Europe and Germany well before potatoes become commonplace. Today, topinambur is considered a standard German vegetable, although most of the national crop is used for the production of a spirit called “Rossler” or simply “Topi”. Topinambur has medicinal properties as it contains insulin and is therefore a suitable dietary supplement for diabetics. When boiled, the tubers have a mild and somewhat sweet taste that truly reminds one of steamed artichokes! We added them to a Lao dish of peanut coconut chicken and sticky rice and it turned out to be a delicious combination.

Lately our wanderings have taken us further north in the city, following the Panke River in search of interesting plants, new foraging grounds, and a better understanding of the natural history that has shaped the area. The underlying landscape found here, like much of the Brandenburg area, was fundamentaly determined by the slow movement of glaciers whose watery fingerprints dotted this sandy, infertile part of the North European Plain with lakes and bogs. Were it not for human intervention, the area would be covered by ancient woodlands, a glimpse of which can be seen in the beech forest of the Schorfheide-Chorin Biosphere Reserve northeast of Berlin. Human presence has reshaped the landscape in unexpected ways, from artificial hills created with war rubble to modern green spaces in the form of carefully designed urban parks. It is in one such green space, namely Bürgerpark in Pankow, where we found the plant that we decided to write about today.

Japanese quince (Chaenomeles speciosa), a spiny shrub native to eastern Asia, reached Europe in the late 18th century and became widely grown as an ornamental plant with striking early spring flowers. Its popularity among European gardeners is easy to understand: the Japanese quince not only has aesthetic appeal but is also a frost-hardy plant that can be horticulturally trained in a number of ways, from serving as a thorny hedge or showy espalier to being potted and grown as a bonsai. For the urban forager, Japanese quince fruits are a welcome addition to the fall harvest. The hard but intensily fragrant pomes ripen in late October and resemble miniature quince (Cydonia oblonga) fruits. The spicy scent of the small fruit promises more than what its astringent taste can offer the hungry forager, but cooking these fruits will quickly get rid of their undesirable tartness. The fact that they are naturally high in pectin content also makes them perfect for jams and jellies. But before you relegate the fruit to the realm of exotica preserves and gardening minutiae, consider its nontrivial medicinal history: Japanese quince has traditionally been used as an anti-inflamatory agent for joint problems and as a general health stimulant. Today, its therapeutic propertires are being investigated in relation to Parkinson’s disease.

In Berlin, Japanese quince is found in parks or hedges around the city, and the characteristic yellow fruits make it easy to identify in the fall. Feel free to use our Berlin Plants map to see where we found them. There is also one location marked on Mundraub, although it is right next to a busy road and hence not suitable for foraging.

A few posts ago we featured the split personality of the European yew: lowly hedge yet powerful, magnificent tree. Today we focus on wolfberry (Lycium barbarum or the closely related Lycium chinense), a hedge plant in Berlin whose double life illustrates the slow-shifting cultural landscape of food. Although the Lycium barbarum is native to both Asia and southeastern Europe, it was first introduced into the UK in the 18th century by Archibald Campbell, an enthusiastic gardener and the 3rd Duke of Argyll (hence another common name for the plant is Duke of Argyll’s tea tree). From here on, the sprawling bush has grown wild in hedgerows or has been used sporadically around Europe as a wind barrier. The characteristic flower betrays its membership in the infamous Nightshade family, and the mature ovoid red berries suspiciously resemble the toxic Amara Dulcis (Solanum dulcamara) fruits. This is most likely why the ripe berries were regarded as poisonous and wolfberry has primarily been valued for its menial hedging habits. In Germany, the toxicity of the plant was investigated in the late 19th century in a doctoral dissertation published in Erlangen. The thesis claimed that Lycium spp. contain pupil-dilating substances, a hallmark of nightshade plants such as Belladonna (Atropa belladonna). As a result, wolfberry fruits were not considered edible until their recent introduction into health food markets as the much awaited panacea from the Far East: Goji berries.

Goji berries have a long, distinguished history in traditional Chinese medicine, from being used to improve vision, cure infertility and dry cough to loftier claims of extending longevity. The berries are consumed in a variety of ways: eaten raw or consumed as fresh juice, wine or tea. The dried berries are often featured in soups. When goji berries were “introduced” in Europe, they were accompanied by incredible medical claims of fighting cancer, and preventing premature aging and memory loss. Regardless of the validity of these medical claims, the berries are chock full of vitamins, minerals and antioxidants. Such treasures come with a heavy price tag; you can expect to pay a minimum of 20 euros per kilogram of dried goji berries in most organic health food stores in Berlin. Meanwhile, among German plant aficionados, an atmosphere of confusion ensues as many find it hard to believe that wolfberry, which is considered an invasive weed, is the source of goji berries. Well, dear reader, rest assured! You can gather goji berries all over Berlin, and they are not toxic (for a recent article on the pharmacology of goji berries see here). However, care must be taken not to mistake the plant for the toxic Amara Dulcis. There is also a potential risk of drug interaction when consuming goji berries, in particular with blood thinners such as Warfarin.

We found wolfberry shrubs along the northern side of the S-bahn ring, west of Schönhauser Alle. All the berries were already gone (as you can see in a picture below) and we were quite disappointed, thinking we would have to wait another year for the harvest. On a whim of the moment, we decided to explore a bit further west in Wedding, looking for interesting plants and keeping our eyes open for goji berries as we walked along the small Panke River. As you can tell from the pictures, our optimism was handsomely rewarded by a bowl full of goji berries! The raw berries are somewhat of an acquired taste, as the initial sweetness of the fruit is followed by a potent, lingering bitterness. We are therefore drying the harvested berries (which should reduce the bitterness) and plan on using them in soups and teas!